Question

Mendel’s dihybrid phenotypic ratio is

• A. 3:1
• B. 1:2:1
• C. 9:3:3:1
• D. 1:1

Answer 1

The correct option is C

9:3:3:1

In Mendel's dihybrid cross, the parents are - plants with round yellow coloured seeds (RRYY) and plants with green coloured wrinkled seeds (rryy). The $F_1$ progeny are all round and yellow seeds (RrYy). Self-fertilizing the $F_1$ plants gives $F_2$ progeny exhibiting 4 different phenotypes. Yellow round (9), yellow wrinkled (3), green round (3), and green wrinkled seed plants (1). The phenotypes with round yellow seeds, wrinkled yellow seeds, round green seeds and wrinkled green seeds are in the ratio 9:3:3:1.